Originally Posted by Llanite
It only works with assassins who do gank a lot + reliable escape ( or crazy range), leblanc, kass, akali or lux.
800 can be translated into 40 AP (blasted wand = 860) which is ~ 5 stacks, hence, only cost-efficient if you can maintain at least 6, and even so, it's still not that good due to inability to upgrade. If you cant keep ~8 stacks the whole game, dont bother.
I used to think like this on LeBlanc, and LeBlanc is the champ I play best with.
I've since changed my tune. I now believe that Mejais is best on ANY champ that has high survivability from start to finish and can rack up a ton of assists throughout the game. I always get it on Mundo and Morgana. Those are two very different champs I can think of that almost always end up with a stacked Mejais.
BTW, a stacked Mejais on Mundo is absolutely beast.
I find that champs who rack up stacks almost entirely through kills and not assists are also the ones that find themselves losing stacks later on. And then it just becomes a burdon you have to sell off, which always sucks.